Organopolysiloxane graft polyester and its manufacturing method

ABSTRACT

An organopolysiloxane graft-type polyester is prepared by reacting, in the presence of an effective amount of a hydrosilylation catalyst, a polyester containing at least one alkenyl group and having no unsaturated terminal groups, said polyester having a number average molecular weight of about 500 to about 5,000, and an organopolysiloxane containing one hydrosilyl group. The organopolysiloxane graft-type polyester has excellent compatibility with polyesters and can improve the surface smoothness and hydrophobic property of the polyester when modified therewith.

This is a divisional of copending application Ser. No. 07/522,753 filedon May 11, 1990, now U.S. Pat. No. 5,082,916.

This invention concerns a type of organopolysiloxane graft polyester andits manufacturing method.

BACKGROUND OF THE INVENTION

It has been well known that polyethylene terephthalate, polybutyleneterephthalate, and other polyesters can be effectively modified by anorganopolysiloxane to obtain improvements in characteristics such as thehydrophobic property, water repellent property, weatherability, andlubricating property.

For example, as disclosed in U.S. Pat. Nos. 4,496,704; 4,452,962; and4,348,510; when a diorganopolysiloxane containing alcoholic hydroxylgroups at its two terminals is added during the polymerization reactionof the polyester, it is possible to obtain a diorganopolysiloxaneblock-type polyester with improved surface smoothness. However, thediorganopolysiloxane-modified polyester obtained in this way has adisadvantage. In order to improve the surface smoothness and hydrophobicproperty by incorporating the diorganopolysiloxane portion into the mainchain of this linear copolymer, the copolymerization rate of thediorganopolysiloxane must be increased. However, as the copolymerizationrate of the diorganopolysiloxane is increased, the characteristics ofthe polyester disappear.

Furthermore, since the diorganopolysiloxane containing alcoholichydroxyl groups at its two terminals lacks compatibility with thestarting material polyester monomer, copolymerization is difficult andthere is a significant residual portion that is not copolymerized.

SUMMARY OF THE INVENTION

In order to develop the manufacturing method of theorganopolysiloxane-modified polyester free of said disadvantages, thepresent inventors have performed intensive research. As a result of thisresearch work, the present invention was attained.

The purpose of this invention is to provide a new type oforganopolysiloxane-modified polyester and a manufacturing methodtherefor. The organopolysiloxane graft-type polyester contains almost nofree organopolysiloxane, it has excellent compatibility with polyesters,and can improve the surface smoothness and hydrophobic property of thepolyester.

The manufacturing method of this invention is characterized by the factthat it can be used to produce the organopolysiloxane graft-typepolyester with a high efficiency.

The present invention therefore relates to an organopolysiloxanegraft-type polyester prepared by reacting, in the presence of aneffective amount of a hydrosilylation catalyst,

(A) a polyester containing at least one alkenyl group and having nounsaturated terminal groups, said polyester having a number averagemolecular weight of about 500 to about 5,000; and

(B) an organopolysiloxane containing one hydrosilyl group.

DETAILED DESCRIPTION OF THE INVENTION

According to this invention, the main chain of the organopolysiloxanegraft-type polyester is a polyester (A), having a organopolysiloxane (B)bonded to its side chain via an alkylene group. The polyester used asthe main chain has a number average molecular weight of about 500 to5000. The polyester may be either an aliphatic polyester or an aromaticpolyester; it may be either a straight chain or branched chain.

The alkylene group for grafting the organopolysiloxane may be bonded toeither the organic carboxylic acid portion or the alcohol portion of thepolyester. The alkylene group may be attached directly to a carbon atomor it may be connected through an oxygen atom. Preferable terminals ofthe polyester include an ester group, followed by a hydroxyl group.

The preferable form of the grafted organopolysiloxane is a straightchain, followed by a branched chain. There is no special limitation onthe degree of polymerization (DP) as long as it is 2 or larger. However,if the DP is too large, handling becomes difficult and its startingpolysiloxane material lacks addition reactivity. Hence, the DP isusually less than about 2,000. From the standpoint of a modificationeffect, the average value of the DP is preferably about 3 to 100.Examples of the siloxane units that form the grafted organopolysiloxaneinclude dimethylsiloxane, methylalkylsiloxane having 2 to 10 carbonatoms in their alkyl radicals, methylphenylsiloxane, methylsiloxane,trimethylsiloxane, dimethylbutylsiloxane, inter alia.

The organopolysiloxane-graft polyester of this invention may be ineither the liquid form or solid form at room temperature.

Preferably, the alkenyl group-containing polyester used as component (A)in this invention should be in a straight chain form or branched chainform, with an ester group and/or a hydroxyl group containing nounsaturated group at the terminals of the molecular chain. In order toperform the grafting hydrosilylation reaction with theorganopolysiloxane (B) containing a silicon-bonded hydrogen group at ahigh efficiency, the number average molecular weight of polyester (A)should be about 500 to 5,000.

Each polyester molecule should contain at least one alkenyl group. Inorder to improve the effectiveness of the organopolysiloxane graft-typepolyester of this invention when used as a polyester modifier, thecontent of the organopolysiloxane should be high, but within the rangefor maintaining compatibility with the polyester. Hence, with respect tothe repetitive units of the polyester, the content of the alkenyl groupsshould be about 20 to 200 mol %, preferably 50 to 100 mol % (i.e., 0.2to 2.0 alkenyl groups for each polyester repeat unit).

The polyester component (A) can be produced using the conventionalpolycondensation method from a polyhydric carboxylic acid, or itsderivative, and a polyhydric alcohol. As determined by the purpose ofthis invention, it is preferred that most of the starting materials be adihydric carboxylic acid, or its derivative, and a dihydric alcohol.

Examples of the dihydric carboxylic acid that can be used includephthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalicacid, tetrachlorophthalic acid, oxalic acid, malonic acid, succinicacid, adipic acid, sebacic acid, cyclopentanedicarboxylic acid, amongothers.

Examples of the dihydric alcohol that can be used include ethyleneglycol, propylene glycol, butanediol, hexamethylene glycol, hydrogenatedbisphenol A, neopentyl glycol, diethylene glycol, triethylene glycol,dipropylene glycol, among others.

The alkenyl groups contained in the polyester (A) are introduced in thepolyhydric carboxylic acid and/or polyhydric alcohol components used asstarting materials. Examples of the components containing alkenyl groupsinclude glycerin monoallyl ether, trimethylolpropane monoallyl ether,pentaerythritol monoallyl ether, pentaerythritol diallyl ether, andother polyhydric alcohols. Alternatively, these components may beselected from allyloxy isophthalic acid, allyloxy terephthalic acid,allyl malonic acid, and other polyhydric carboxylic acids. Depending onthe copolymerization method, the polyhydric carboxylic acid component isadded in an appropriate form, such as a carboxylic acid or its alkylester, halide, or other derivative.

Any of the following methods can be used to manufacture the polyesterusing polycondensation: a method using dehydration condensation of apolyhydric carboxylic acid and polyhydric alcohol; a method of thetransesterification of a polycarboxylic ester and polyhydric alcohol;and a method of the hydrochloric acid dehydrogenation condensation of ahalide of a polyhydric carboxylic acid and a polyalcohol in the presenceof a base.

The molecular weight of the polyester depends on the ratio of thepolyhydric carboxylic acid, or its derivative, to the polyhydricalcohol. That is, when the amount of the polyhydric carboxylic acid, orits derivative, added is in excess with respect to the polyhydricalcohol, the terminal groups become carboxylic acid, or its derivative.

According to this invention components (A) and (B) undergo ahydrosilylation reaction. Therefore, the terminal groups of thepolyester should not hamper this reaction, nor should they induce sidereactions. It is thus preferred that the terminal groups of thepolyester be ester groups containing no unsaturated group. The terminalester groups may be introduced by adding an appropriate amount of amonohydric alcohol component during the polycondensation reaction.However, when the organopolysiloxane graft-type polyester of thisinvention is used as a modifier for a polyester, it is necessary toeffectively strip out the monohydric alcohol formed in thetransesterification reaction from the reactive system. It is thereforepreferred that the monohydric alcohol have about 1 to 12 carbon atoms, 1to 6 carbon atoms being highly preferred. When a polyhydric carboxylicester is used as the starting material, the ester portion of itsconfiguration becomes the terminal group; hence, there is no need to adda monohydric alcohol component in this case.

When the amount of the polyhydric alcohol used is in excess with respectto that of the polyhydric carboxylic acid, or its derivative, apolyester having hydroxyl groups at its terminals can be obtained. Inthis case, there is the possibility of a condensation between thehydroxyl group and the SiH group in the subsequent hydrosilylationreaction. However, this reactivity is usually much lower than that ofthe hydrosilylation reaction, and hence causes no significant problem.If it is necessary to completely inhibit this side reaction, theterminal hydroxyl groups can be protected by a conventional silylatingagent.

The organopolysiloxane (B) containing a hydrosilyl group may be in theform of a straight chain, branched chain, or network structure as longas each molecule contains one hydrosilyl (i.e., SiH) group. Among these,the straight chain form organopolysiloxane with one terminal having ahydrosilyl group is preferred. In this case, the other terminal of theorganopolysiloxane may be, for example, a trialkysilyl group such astrimethylsilyl or n-butyldimethylsilyl. The organopolysiloxane can beproduced using a conventional method. There is no special limitation onits molecular weight. However, in order to improve the polyestermodification effect by the organopolysiloxane graft-type polyester ofthis invention, the average DP of the siloxane units should be in therange of about 3 to 100, preferably 5 to 50.

Examples of the organic groups bonded with the silicon atoms oforganopolysiloxane (B) include methyl, ethyl, propyl, butyl, pentyl,hexyl, heptyl, octyl, and other alkyl groups; phenyl, naphthyl, andother aryl groups; benzyl group, phenethyl group, and other aralkylgroups; methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy,heptyloxy, octyloxy group, and other alkoxy groups; phenoxy, naphthyloxygroup, and other aryloxy groups; etc. In addition, there may also be asmall amount of hydroxyl groups and amino groups bonded with the siliconatoms. In consideration of cost and performance, it is preferred thatover half of the organic groups bonded with the silicon atoms be methylgroups.

There is no special limitation on the type of the hydrosilylationcatalyst (C) used to promote reaction between components (A) and (B).The catalyst may be made of the well-known complexes of transitionmetals, such as platinum, palladium, rhodium, ruthenium, cobalt, nickel,etc. In particular, chloroplatinic acid, a platinum olefin complex, acomplex of chloroplatinic acid and vinylsiloxane, and otherplatinum-family catalysts are preferred since they have a high catalyticeffect and lead to few side reactions.

In the presence of the catalyst, the alkenyl groups of component (A) andthe hydrosilyl groups of component (B) undergo an addition reaction toform the organopolysiloxane graft-type polyester of this invention. Itis preferred that this addition reaction be performed with theappropriate ratio of component (A) to component (B) to ensure anequivalent or near equivalent molar amount of alkenyl groups andhydrosilyl groups. This addition reaction may be performed at anytemperature from room temperature to 150° C., preferably 60° C. to 150°C. in order to shorten the reaction time and suppress side reactions. Itis preferred to carry out the addition reaction in the presence of asolvent. This improves the reaction at a high efficiency sincecomponents (A) and (B) usually have a low compatibility with each other.

The solvent used should be able to dissolve both components (A) and (B),and may be selected from benzene, toluene, xylene, and other aromatichydrocarbons as well as diethyl ether, tetrahydrofuran, and otherethers.

The organopolysiloxane graft-type polyester of this invention can beused as a coating agent, polyester additive, copolymerization componentof the polyester, modifier of resins other than a polyester, inter alia.

EXAMPLES

In the following, this invention will be explained in more detail withreference to application examples, wherein "parts" refers to "parts byweight." Of course, these application examples do not limit the range ofthis invention.

APPLICATION EXAMPLE 1

10.2 parts of terephthaloyl dichloride and 30.0 parts of tetrahydrofuranwere added to a dried reaction container equipped with a stirrer. Whilethe reaction container was cooled, the mixture was stirred. A solutionprepared by dissolving 7.8 parts of trimethylolpropane monoallyl etherand 11.1 parts of triethylamine in 12.0 parts of tetrahydrofuran wasdripped in over a period of about 40 minutes, followed by heating toroom temperature and stirring for 3 hours.

The reaction container was then cooled again by ice water, and 0.5 partof methanol was added to the reaction solution, followed by heating to60° C. and stirring for 1 hour.

After cooling, the precipitate formed was filtered off and the filtratewas concentrated at a reduced pressure. The residue was diluted withabout 50 parts of ethyl acetate, washed 3 times with the same amount ofwater, and dried with anhydrous sodium sulfate. After filtration, thefiltrate was concentrated under reduced pressure, forming a very thicklight-yellow liquid, which was analyzed and found to be a polyester withan average molecular weight of 2,560 and having 8.2 wt % of vinyl groups(--CH═CH₂) on the side chains.

In a dried reaction container equipped with a stirrer, 10.5 parts of thepolyester obtained in the above operation and 50.0 parts of apolydimethylsiloxane having a molecular weight of 1,580, one terminalblocked by a hydrosilyl group and the other terminal blocked by ann-butyl group were weighed and dissolved in 200 parts oftetrahydrofuran. There was then added 0.2 part of an isopropyl alcoholsolution of chloroplatinic acid (platinum concentration: 0.4 wt %). Anaddition reaction was then performed by heating the mixture to reflux.

The reaction was monitored by a gel permeation chromatograph equippedwith a detector for the 9.5-μ IR band (characteristic absorption ofsiloxane) and a detector for 254-nm UV band (characteristic absorptionof the benzene ring). In the initial period of the reaction, the peak ofthe polydimethylsiloxane detected by IR and the peak of the polyesterdetected by UV were observed with different retention times. After areaction for 4 hours, the retention times of the peaks observed on thetwo detectors shifted to higher molecular weight side and became almostidentical. Hence, it was determined that the polyester withpolydimethylsiloxane grafted via a propylene group was obtained. Thenumber-average molecular weight of the obtained polydimethylsiloxanegraft-type polyester was 9,360 (standard polystyrene equivalent). Afterthe reaction, concentration under reduced pressure was performed,obtaining a light-yellow transparent liquid, in which the freepolydimethylsiloxane was present in a trace amount.

When the above liquid was added to polyethylene terephthalate, thecompatibility was found to be good, there was no bleeding, and thesurface smoothness and hydrophobic property were significantly improved.

APPLICATION EXAMPLE 2

11.7 parts of allyoxy isophthaloyldichloride and 30.0 parts oftetrahydrofuran were loaded into a dried reaction container equippedwith a stirrer. While the reaction container was cooled by ice water,the mixture was stirred. A solution prepared by dissolving 5.2 parts ofneopentyl glycol and 11.2 parts of triethylamine in 10.0 parts oftetrahydrofuran was dripped in over a period of about 30 minutes,followed by heating to room temperature and stirring for 5 hours. Thereaction container was cooled again with ice water, then 0.5 part ofmethanol was added to the reaction solution, followed by heating to 60°C. and stirring for 1 hour.

After the resulting precipitate was filtered, the filtrate wasconcentrated under reduced pressure. The obtained residue was dried anddissolved in about 100 parts of acetone. After the insoluble portion wasfiltered off, the filtrate was again concentrated under reducedpressure, forming a light-yellow solid.

The analysis indicated that it was a polyester with an average molecularweight of 3,269 and having 9.7 wt % of vinyl groups (--CH═CH₂) in theside chains.

In a dried reaction container equipped with a stirrer, 55.6 parts of thepolyester obtained in the aforementioned operation, and 10.0 parts ofpolydimethylsiloxane (molecular weight=1,580, one terminal blocked by ahydrosilyl group and the other terminal blocked by an n-butyl group)were weighed and dissolved in 200 parts of tetrahydrofuran.Subsequently, 0.02 part of a platinum-vinyl siloxane complex (platinumconcentration: 4.4 wt %) prepared from chloroplatinic acid and1,3-divinyltetramethyldisiloxane was added. The reaction mixture wasthen heated to reflux to facilitate the addition reaction.

In the same way as in Application Example 1, the reaction was monitoredby a gel permeation chromatograph. It was found that a polyester withpolydimethylsiloxane grafted via a propylene group was obtained.

The number-average molecular weight of the obtained polydimethylsiloxanegraft-type polyester was 15,730 (standard polystyrene equivalent). Afterthe addition reaction, by concentration under reduced pressure, alight-yellow transparent liquid was obtained. In this liquid, the freepolydimethylsiloxane was present in a trace amount.

This liquid was added during the polymerization of polyethyleneterephthalate. As a result, the surface smoothness and the hydrophobicproperty were significantly improved.

APPLICATION EXAMPLE 3

15.2 parts of terephthaloyldichloride and 35.0 parts of tetrahydrofuranwere added to a dried reaction container equipped with a stirrer. Whilethe reaction container was cooled by ice water, the mixture was stirred.

A solution prepared by dissolving 7.8 parts of trimethylolpropanemonoallyl ether, 1.4 parts of ethylene glycol, and 16.7 parts oftriethylamine in 15.0 parts of tetrahydrofuran was dripped in over aperiod of about 40 minutes. The mixture was heated to room temperatureand stirred for 3 hours. It was then cooled again by ice water and addedwith 0.7 part of methanol, followed by heating to 60° C. and stirringfor 1 hour. After the reaction mixture was cooled, the resultingprecipitate was filtered and the filtrate was concentrated under reducedpressure. The residue was diluted with about 100 parts of ethyl acetate,then washed three times with the same amount of water, and dried withanhydrous sodium sulfate. After filtration, the filtrate wasconcentrated under reduced pressure to form a very thick light-yellowliquid. The analysis indicated that it was a polyester having an averagemolecular weight of 1,640 and containing 5.9 wt % of vinyl groups(--CH═CH₂) in the side chains.

In a dried reaction container equipped with a stirrer, 14.7 parts of thepolyester obtained above and 50.0 parts of polydimethylsiloxane(molecular weight=1,580, one terminal blocked by a hydrosilyl group andthe other terminal blocked by an n-butyl group) were weighed anddissolved in 200 parts of tetrahydrofuran. Subsequently, 0.02 parts of aplatinum-vinyl siloxane complex (platinum concentration: 4.4 wt %) wasadded. The addition reaction was then performed by heating the mixtureat reflux for 5 hours. In the same way as in Application Example 1, thereaction was monitored by a gel permeation chromatograph. It wasconfirmed that the polyester with polydimethylsiloxane grafted via apropylene group was obtained. The obtained polydimethylsiloxanegraft-type polyester had a number-average molecular weight of 4,600(standard polystyrene equivalent). After the reaction, concentrationunder reduced pressure was performed, forming a light-yellow,transparent, thick liquid. In this liquid, the free polydimethylsiloxanewas present in a trace amount.

APPLICATION EXAMPLE 4

7.1 parts of the polyester containing allyl groups prepared inApplication Example 3 and 50.0 parts of polydimethylsiloxane (molecularweight=3,250, one terminal blocked by a hydrosilyl group and the otherterminal blocked by an n-butyl group) were weighted and dissolved in 200parts of tetrahydrofuran. Subsequently, 0.02 part of aplatinum-vinylsiloxane complex (platinum concentration: 4.4 wt %)prepared from chloroplatinic acid and 1,3-divinyltetramethyldisiloxanewas added. The addition reaction was then performed by heating themixture at reflux for 5 hours. In the same way as in Application Example1, a gel permeation chromatograph was used to monitor the additionreaction. It was confirmed that a polyester with polydimethylsiloxanegrafted via a propylene group was obtained. The obtainedpolydimethylsiloxane graft-type polyester had a number-average molecularweight of 15,200 (standard polystyrene equivalent). After the reaction,the reaction product was concentrated under reduced pressure to form alight-yellow transparent thick liquid. In this liquid, the freepolydimethylsiloxane was present in a trace amount.

We claim:
 1. A polyester modified with a polydimethylsiloxane graft-typepolyester characterized by the fact that said polydimethylsiloxane isgrafted onto the side chain of a polyester having a number averagemolecular weight of 500 to 5,000 via an alkylene group.
 2. The polyesteraccording to claim 1, wherein said polydimethylsiloxane has a straightchain structure.
 3. The polyester according to claim 2, wherein thedegree of polymerization of said polydimethylsiloxane is about 5 to 50.4. A composition consisting essentially of a polyester which is modifiedwith a polydimethylsiloxane graft-type polyester, said graft-typepolyester being prepared by reacting, in the presence of an effectiveamount of a hydrosilylation catalyst, (A) a polyester containing atleast one alkenyl group and having no unsaturated terminal groups, saidpolyester having a number average molecular weight of about 500 to about5,000; and (B) a polydimethylsiloxane containing one hydrosilyl group.5. The composition according to claim 4, wherein saidpolydimethylsiloxane is a straight chain structure having a hydrosilylgroup at one end of the chain and the ratio of components (A) and (B) isfixed so as to provide approximately one hydrosilyl group for reactionwith each alkenyl group.
 6. The composition according to claim 5,wherein the degree of polymerization of said polydimethylsiloxane isabout 5 to 50.